mirror of
https://github.com/esphome/esphome-docs.git
synced 2024-12-28 17:48:35 +01:00
59 lines
2.3 KiB
ReStructuredText
59 lines
2.3 KiB
ReStructuredText
.. _uart:
|
|
|
|
UART Bus
|
|
========
|
|
|
|
.. seo::
|
|
:description: Instructions for setting up a UART serial bus on ESPs
|
|
:image: uart.svg
|
|
:keywords: UART, serial bus
|
|
|
|
UART is a common serial protocol for a lot of devices. For example, when uploading a binary to your ESP
|
|
you have probably used UART to access the chip. UART (or for Arduino often also called Serial) usually
|
|
consists of 2 pins:
|
|
|
|
- **TX**: This line is used to send data to the device at the other end.
|
|
- **RX**: This line is used to receive data from the device at the other end.
|
|
|
|
Please note that these the naming of these two pins depends on the chosen perspective and can be ambiguous. For example,
|
|
while the ESP might send (``TX``) on pin A and receive (``RX``) data on pin B, from the other devices
|
|
perspective these two pins are switched (i.e. *it* sends on pin B and receives on pin A). So you might
|
|
need to try with the two pins switched if it doesn't work immediately.
|
|
|
|
Additionally, each UART bus can operate at different speeds (baud rates), so esphomelib needs to know what speed to
|
|
receive/send data at using the ``baud_rate`` option. The most common baud rates are 9600 and 115200.
|
|
|
|
In some cases only **TX** or **RX** exists as the device at the other end only accepts data or sends data.
|
|
|
|
.. note::
|
|
|
|
On the ESP32, this component uses the hardware UART units and is thus very accurate. On the ESP8266 however,
|
|
esphomelib has to use a software implementation as there are no other hardware UART units available other than the
|
|
ones used for logging. Therefore the UART data on the ESP8266 can have occasional data glitches especially with
|
|
higher baud rates..
|
|
|
|
.. code:: yaml
|
|
|
|
# Example configuration entry
|
|
uart:
|
|
tx_pin: D0
|
|
rx_pin: D1
|
|
baud_rate: 9600
|
|
|
|
|
|
Configuration variables:
|
|
------------------------
|
|
|
|
- **baud_rate** (**Required**, int): The baud rate of the UART bus.
|
|
- **tx_pin** (*Optional*, :ref:`config-pin`): The pin to send data to from the ESP's perspective.
|
|
- **rx_pin** (*Optional*, :ref:`config-pin`): The pin to receive data on from the ESP's perspective.
|
|
- **id** (*Optional*, :ref:`config-id`): Manually specify the ID for this UART hub if you need multiple UART hubs.
|
|
|
|
See Also
|
|
--------
|
|
|
|
- :doc:`API Reference </api/core/uart>`
|
|
- `Edit this page on GitHub <https://github.com/OttoWinter/esphomedocs/blob/current/esphomeyaml/components/uart.rst>`__
|
|
|
|
.. disqus::
|